Prof. David Dunkerley - Honours Projects

Characteristics and ecohydrological role of ground litter layers.

Supervisor: David Dunkerley

Organic litter accumulates beneath many vegetation communities, from arid shrublands to tropical forests. Though a significant amount is known from some locations about the rate of litter fall, far less is known about how litter modifies the movement of rainfall and throughfall into the soil or over its surface as overland flow. Litter both intercepts some rainfall and throughfall, preventing its entry into the plant root zone, and may also promote overland flow on or within the litter (termed 'biomat flow'), again reducing opportunities for infiltration. Very little is known about the effects of litter on soil splash and erosion.

This project would explore some aspects of litter and its role in one or more environments in Victoria, perhaps including a mallee location and a wet sclerophyll forest. The research would involve the installation of automated devices to record rainfall, throughfall, and the percolation of water through the litter layers.

The project might valuably focus on management fires that are widely used to reduce fuel loads and the risk of wildfire. In Victoria, virtually nothing is known about what this practice does to litter and its role.

For further information contact: David Dunkerley

Monitoring stemflow using chemical flux integrators

Supervisor: David Dunkerley

There is a growing realisation of the importance of various pathways by which water reaches the plant root zone. In some crop and forest plants, more than half of the water arrives by trickle flow down the plant itself, as stemflow. However, this process is complex and is affected by weather conditions, by rainfall intensity, duration, and other properties, and by plant architecture. Importantly, stemflow has different chemical and isotopic properties to rainfall or free throughfall, and is involved in delivering nutrients to the root zone. One technical challenge is to monitor stemflow on a sufficient sample of plant taxa that the overall effect on water and nutrient balance can be estimated.

This project would the potential to use economical chemical flux integrators (recording the mass loss of sparingly soluble materials) set up as stemflow recorders. Such devices have never been employed in this way, though their use in recording throughfall is established. Their great advantages are very low cost, facilitating large sample sizes, and the elimination of traditional collecting vessels, which commonly overflow between field visits, resulting in data loss. This project would ideally be based in a mallee field area, since the architecture of these plants is considered to involve very efficient (and ecologically important) stemflow delivery, even from small showers of rain.

For further information contact: David Dunkerley